I have found the following problem when including an external PDF with \externalfigure:

Some (or all?) values in PDF arrays that are between -1.0 and 0.0 loose their minus sign. E.g:

-0.1 turns into 0.1. This can lead to significant visual differences. This problem did not exist in earlier versions of ConTeXt.

For a MWE consider the following:

where test.pdf is attached and has a MediaBox [-0.1 -0.1 612 792]. In the PDF produced by ConTeXt test.pdf is correctly put in an XObject but this XObject now has a BBox [0.1 0.1 612 792].

I am afraid but this might be a bug in newer versions of luatex. I would greatly appreciate if this would be addressed.

Kind regards,

Christoph